Millisecond Forums

control max trial type in a row

https://forums.millisecond.com/Topic28053.aspx

By lir1995 - 12/2/2019

Hi Dave, 

Is there a way in Inquisit to control for the number of the same type of trial that occurs in a row (either by trial type or the type of response made). For example, if my experiment switches between correct and incorrect trials, I do not want more than 4 correct trials in a row to limit participants from pressing yes so many times in a row. Ideally, this would be based on the trial type itself, regardless of how the participant actually responds. Is there a way to do this? 

I had tried doing this using the branching attribute, but was unsuccessful. 

Thanks!!
By Dave - 12/2/2019

lir1995 - 12/2/2019
Hi Dave, 

Is there a way in Inquisit to control for the number of the same type of trial that occurs in a row (either by trial type or the type of response made). For example, if my experiment switches between correct and incorrect trials, I do not want more than 4 correct trials in a row to limit participants from pressing yes so many times in a row. Ideally, this would be based on the trial type itself, regardless of how the participant actually responds. Is there a way to do this? 

I had tried doing this using the branching attribute, but was unsuccessful. 

Thanks!!

Yes, you can do so by sampling trials from a <list> and setting the list's /maxrunsize according to your needs. Suppose you have two <trial> elements A and B, 20 trials total (10 x A, 10 x  B), and want to allow a maximum of 3 trials of the same type in a row. Then you do:

<trial a>
...
</trial>

<trial b>
...
</trial>

<list triallist>
/ items = (trial.a, trial.b)
/ poolsize = 20
/ maxrunsize = 3
</list>

with

<block example>
/ trials = [1-20 = list.triallist]
</block>